REST API authentication#
Initiate a request#
All REST private request headers must contain the following:
- OK-ACCESS-KEYstring APIKey(follow [this guide])(./introduction-to-developer-portal-interface#generate-api-keys) to generate an API key
- OK-ACCESS-SIGNuses the HMAC SHA256 hash function to get the hash value, then uses Base-64 encoding (see signature)
- OK-ACCESS-TIMESTAMPspecifies the time (UTC) when the request is initiated, for example, 2020-12-08T09:08:57.715Z
- OK-ACCESS-PASSPHRASErepresents the Passphrase you specified when creating the API key
Some endpoints, require additional headers:
- OK-ACCESS-PROJECTThe project ID of your project (found under Project Details)
All requests should have content of type 'application/json' and be valid JSON.
Signature#
OK-ACCESS-SIGNrequest header:
- is a combination of timestamp + method + requestPath + body strings (+ indicates string connection) and SecretKey, which is encrypted using the HMAC SHA256 method and output through Base-64 encoding.
- Prepare the Secret Key (generated when the API key is created).
- Use HMAC SHA256 to sign the pre-hash string with a key.
- Encodes the signature in Base64 format.
Example:
sign=CryptoJS.enc.Base64.stringify(CryptoJS.HmacSHA256(timestamp + 'GET' + '/api/v5/account/balance?ccy=BTC', SecretKey))
- The value of 'timestamp' is the same as the request header of 'OK-ACCESS-TIMESTAMP' and is in ISO format
- For example:2020-12-08T09:08:57.715Z
 
- For example:
- method indicates the request method. All letters are uppercase
- For example:GET/POST
 
- For example:
- requestPath specifies the request interface path
- For example:/api/v5/account/balance
 
- For example:
- body is the string that requests the body. If the request does not have a body (usually a GET request), the body can be omitted
- For example:{"instId":"BTC-USDT","lever":"5","mgnMode":"isolated"}
- GETthe request parameter is counted as requestPath, not body
 
- For example:
Postman example#
Postman is a popular API development and testing tool that allows developers to design, test, and document APIs. It provides a user-friendly graphical interface for making HTTP requests to APIs.
If you have not installed Postman, you can download it for free from the Postman website: https://www.postman.com/
Add parameters#
- This typically applies to GET requests.
- If your request requires query parameters, you can add them under the Params tab. Here, you can add key-value pairs for your query parameters.
Set headers#
Under the Headers tab, add the following key-value pairs:
- OK-ACCESS-KEY
- OK-ACCESS-PASSPHRASE
- OK-ACCESS-PROJECT(if required)
Add body#
- This typically applies to POST requests.
- If your request requires a request body, you can add them under the Body tab.
- Select raw and JSON under the dropdown menu.
- Input your request body in JSON format.
Set pre-request script#
- This is used to generate the necessary signature (OK-ACCESS-SIGN) and timestamp (OK-ACCESS-TIMESTAMP)
- Under the Pre-request Script tab, insert the script which corresponds to the request type.
- Exclude the request body when generating the prehash string for GET requests.
- Edit the secret key accordingly.
GET requests:
var method = pm.request.method;
var now = new Date();
var isoString = now.toISOString();
var path = pm.request.url.getPathWithQuery();
var sign=CryptoJS.enc.Base64.stringify(CryptoJS.HmacSHA256(isoString + method + path, pm.variables.replaceIn('{{secret_key}}')));
pm.request.headers.add({
    key: 'OK-ACCESS-SIGN',
    value: sign
});
pm.request.headers.add({
    key: 'OK-ACCESS-TIMESTAMP',
    value: isoString
});
POST requests:
var method = pm.request.method;
var now = new Date();
var isoString = now.toISOString();
var path = pm.request.url.getPathWithQuery();
var bodyStr = pm.request.body.raw;
var sign=CryptoJS.enc.Base64.stringify(CryptoJS.HmacSHA256(isoString + method + path + bodyStr, pm.variables.replaceIn('{{secret_key}}')))
pm.request.headers.add({
    key: 'OK-ACCESS-SIGN',
    value: sign
});
pm.request.headers.add({
    key: 'OK-ACCESS-TIMESTAMP',
    value: isoString
});
Javascript example#
To invoke the API through a Javascript script, refer to the following code example:
const https = require('https');
const crypto = require('crypto');
const querystring = require('querystring');
// Define API credentials and project ids
const api_config = {
  "api_key": '',
  "secret_key": '',
  "passphrase": '',
  "project": '' // This applies only to onchainOS APIs
};
function preHash(timestamp, method, request_path, params) {
  // Create a pre-signature based on strings and parameters
  let query_string = '';
  if (method === 'GET' && params) {
    query_string = '?' + querystring.stringify(params);
  }
  if (method === 'POST' && params) {
    query_string = JSON.stringify(params);
  }
  return timestamp + method + request_path + query_string;
}
function sign(message, secret_key) {
  // Use HMAC-SHA256 to sign the pre-signed string
  const hmac = crypto.createHmac('sha256', secret_key);
  hmac.update(message);
  return hmac.digest('base64');
}
function createSignature(method, request_path, params) {
  // Get the timestamp in ISO 8601 format
  const timestamp = new Date().toISOString().slice(0, -5) + 'Z';
  // Generate a signature
  const message = preHash(timestamp, method, request_path, params);
  const signature = sign(message, api_config['secret_key']);
  return { signature, timestamp };
}
function sendGetRequest(request_path, params) {
  // Generate a signature
  const { signature, timestamp } = createSignature("GET", request_path, params);
  // Generate the request header
  const headers = {
    'OK-ACCESS-KEY': api_config['api_key'],
    'OK-ACCESS-SIGN': signature,
    'OK-ACCESS-TIMESTAMP': timestamp,
    'OK-ACCESS-PASSPHRASE': api_config['passphrase'],
    'OK-ACCESS-PROJECT': api_config['project'] // This applies only to WaaS APIs
  };
  const options = {
    hostname: 'web3.okx.com',
    path: request_path + (params ? `?${querystring.stringify(params)}` : ''),
    method: 'GET',
    headers: headers
  };
  const req = https.request(options, (res) => {
    let data = '';
    res.on('data', (chunk) => {
      data += chunk;
    });
    res.on('end', () => {
      console.log(data);
    });
  });
  req.end();
}
function sendPostRequest(request_path, params) {
  // Generate a signature
  const { signature, timestamp } = createSignature("POST", request_path, params);
  // Generate the request header
  const headers = {
    'OK-ACCESS-KEY': api_config['api_key'],
    'OK-ACCESS-SIGN': signature,
    'OK-ACCESS-TIMESTAMP': timestamp,
    'OK-ACCESS-PASSPHRASE': api_config['passphrase'],
    'OK-ACCESS-PROJECT': api_config['project'], // This applies only to WaaS APIs
    'Content-Type': 'application/json' // POST requests need this header
  };
  const options = {
    hostname: 'web3.okx.com',
    path: request_path,
    method: 'POST',
    headers: headers
  };
  const req = https.request(options, (res) => {
    let data = '';
    res.on('data', (chunk) => {
      data += chunk;
    });
    res.on('end', () => {
      console.log(data);
    });
  });
  if (params) {
    req.write(JSON.stringify(params));
  }
  req.end();
}
// GET request example
const getRequestPath = '/api/v5/dex/aggregator/quote';
const getParams = {
  'chainId': 42161,
  'amount': 1000000000000,
  'toTokenAddress': '0xff970a61a04b1ca14834a43f5de4533ebddb5cc8',
  'fromTokenAddress': '0x82aF49447D8a07e3bd95BD0d56f35241523fBab1'
};
sendGetRequest(getRequestPath, getParams);
// POST request example
const postRequestPath = '/api/v5/mktplace/nft/ordinals/listings';
const postParams = {
  'slug': 'sats'
};
sendPostRequest(postRequestPath, postParams);
